plugin/forward: add it (#1447)

* plugin/forward: add it

This moves coredns/forward into CoreDNS. Fixes as a few bugs, adds a
policy option and more tests to the plugin.

Update the documentation, test IPv6 address and add persistent tests.

* Always use random policy when spraying

* include scrub fix here as well

* use correct var name

* Code review

* go vet

* Move logging to metrcs

* Small readme updates

* Fix readme

plugin/forward/setup_test.go

@@ -0,0 +1,68 @@
+package forward
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/mholt/caddy"
+)
+
+func TestSetup(t *testing.T) {
+	tests := []struct {
+		input            string
+		shouldErr        bool
+		expectedFrom     string
+		expectedIgnored  []string
+		expectedFails    uint32
+		expectedForceTCP bool
+		expectedErr      string
+	}{
+		// positive
+		{"forward . 127.0.0.1", false, ".", nil, 2, false, ""},
+		{"forward . 127.0.0.1 {\nexcept miek.nl\n}\n", false, ".", nil, 2, false, ""},
+		{"forward . 127.0.0.1 {\nmax_fails 3\n}\n", false, ".", nil, 3, false, ""},
+		{"forward . 127.0.0.1 {\nforce_tcp\n}\n", false, ".", nil, 2, true, ""},
+		{"forward . 127.0.0.1:53", false, ".", nil, 2, false, ""},
+		{"forward . 127.0.0.1:8080", false, ".", nil, 2, false, ""},
+		{"forward . [::1]:53", false, ".", nil, 2, false, ""},
+		{"forward . [2003::1]:53", false, ".", nil, 2, false, ""},
+		// negative
+		{"forward . a27.0.0.1", true, "", nil, 0, false, "not an IP"},
+		{"forward . 127.0.0.1 {\nblaatl\n}\n", true, "", nil, 0, false, "unknown property"},
+	}
+
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.input)
+		f, err := parseForward(c)
+
+		if test.shouldErr && err == nil {
+			t.Errorf("Test %d: expected error but found %s for input %s", i, err, test.input)
+		}
+
+		if err != nil {
+			if !test.shouldErr {
+				t.Errorf("Test %d: expected no error but found one for input %s, got: %v", i, test.input, err)
+			}
+
+			if !strings.Contains(err.Error(), test.expectedErr) {
+				t.Errorf("Test %d: expected error to contain: %v, found error: %v, input: %s", i, test.expectedErr, err, test.input)
+			}
+		}
+
+		if !test.shouldErr && f.from != test.expectedFrom {
+			t.Errorf("Test %d: expected: %s, got: %s", i, test.expectedFrom, f.from)
+		}
+		if !test.shouldErr && test.expectedIgnored != nil {
+			if !reflect.DeepEqual(f.ignored, test.expectedIgnored) {
+				t.Errorf("Test %d: expected: %q, actual: %q", i, test.expectedIgnored, f.ignored)
+			}
+		}
+		if !test.shouldErr && f.maxfails != test.expectedFails {
+			t.Errorf("Test %d: expected: %d, got: %d", i, test.expectedFails, f.maxfails)
+		}
+		if !test.shouldErr && f.forceTCP != test.expectedForceTCP {
+			t.Errorf("Test %d: expected: %t, got: %t", i, test.expectedForceTCP, f.forceTCP)
+		}
+	}
+}